This invention pertains to a method and apparatus for introducing various ingredients in solid form into a soap ma for the ultimate manufacture of soap bars. More particularly, this invention is directed to producing soap bars having a multicolored or marbled appearance and made from a variety of different colored soap materials. This invention also includes a method and apparatus for introducing ingredients other than different colored soap materials into a soap mass, such other ingredients including those which may be sensitive to the grinding and crushing forces normally found in soap making techniques.
In the soap art there are two basic systems for producing marbleized soap bars. One is called a solid/liquid system and involves the introduction of a colored liquid into a soap mass during working or plodding of the soap to get a bar with a marbled appearance such as disclosed in U.S. Pat. No. 3,485,905 to Compa.
A second system is called a solid/solid system and involves mixing through a variety of techniques different colored non-liquid soap materials to form the marbleized bar.
There can be difficulties with the use of either system. For example, in the solid/liquid systems, the striped or marbleized effects can be unsatisfactory because they are smeared or even disappear entirely. Also, the equipment required to inject a liquid dye into the soap mass to produce the marbled effect is often very complicated and therefore expensive to make, use and service. In the solid/solid system there have been reports of marbleized bars that suffer from defects such as splitting and face cracking due to the inability of the different soap elements of the bar to adequately bond together. Even more importantly, a number of techniques can not produce a bar having a discreet marble pattern with no smearing.
Furthermore, the methods and equipment employed in most solid/solid systems, that is particularly in the plodding operation, would not be suitable to preserve the integrity of sensitive materials desired to be added to soap bars such as encapsulated dyes, fragrances and the like.
This invention pertains to a method and apparatus for introducing various additives in solid form into a soap mass for the ultimate manufacture of soap bars. As used in this specification and appended claims the terms soap, soap materials or soap bars will include water soluble soaps made from alkali salts of C8-C22 fatty acids as well as products made from synthetic detergents or a mixture of water soluble soap and synthetic detergents. In one aspect, this invention is directed to producing soap bars having a multicolored or marbleized appearance and made from a variety of different colored soap materials. The method and apparatus of this invention is also useful for introducing ingredients or additives in solid form other than different colored soap materials into a soap mass, such other ingredients including those which may be particularly sensitive to the grinding and crushing forces normally found in soap making procedures. Such other additives or ingredients which can be incorporated into a soap mass and ultimately into a soap bar include encapsulated dyes or fragrances. The microcapsules that are normally used to encapsulate dyes, fragrance and the like are usually sensitive to the grinding forces found in soap making and this method and apparatus can be used to preserve the integrity of such capsules. Other encapsulated materials which can be introduced into the soap mass include sunscreens, skin moisturizers and conditioners, personal deodorants or antibacterial agents and the like.
In one aspect the method involves introducing solid soap in pellet or granular form of one color into a soap plodder as is customary. A second or alternate color of soap pellet is separately introduced into the interior of the plodder just before that point where the helical screw of the plodder enters the barrel of the extruder portion of the plodder. The plodder is structurally modified so that the second or alternate color is introduced into the plodder by means of a special pellet feeding apparatus which not only controls the rate of delivery of the alternate color soap pellets but insures that such pellets are introduced into a chamber formed by a flight of the helical screw immediately before the point where the screw enters the plodder barrel. When the alternate color pellet is introduced at this particular point in the plodder apparatus, a very discreet marble pattern in the soap bar is the result and very little if any smearing of the contrasting colors takes place.
If it is desired to introduce ingredients or additives other than a second or alternate color soap pellet into the soap mass, that is a non-soap ingredient in solid form such as an encapsulated fragrance or color, such capsules can be introduced into the interior of the plodder at the same point that the introduction of the second color soap pellet takes place. That is, into a chamber formed by adjacent flights of the helical screw immediately before the point where the screw enters the plodder barrel. The same special pellet feeding apparatus can be used to introduce the non-soap solid material, as used to introduce the colored soap pellets. Such non-soap solid materials can be added either along with the colored soap pellets or they can be introduced independent of one another.